1) Field of the Invention
The invention herein relates to a pin removal structure used in printed circuit board drilling machine.
2) Description of the Prior Art
Printed circuit board (PCB) drilling machines are equipped with PCB carrying plates on their drilling platforms to provide for circuit board placement; enabling the drilling of each hole at the exact predetermined positions in the circuit board for the rapid and convenient drilling of circuit boards of the same specifications. Each circuit board specification also includes a quantity of pin holes at predetermined points for the driving in of locating pins that protrude from the circuit board surface and directly provide for keeping the circuit board stationary, the precise positioning of the circuit board affording accurate drilling efficiency. Additionally, since circuit board specifications vary and the said locating pin drilling points are not identical, the locating pins in the circuit boards must be repeatedly extracted and implanted to accommodate circuit board differences.
The current method of extracting locating pins, as indicated in FIG. 1 and FIG. 2, typically consists of a scissor-type pincing tool 70 that clamps the locating pin A, following which the curved bottom section 701 functions as a fulcrum against the circuit board carrying plate B, and the operator presses down the handle ends 702, the prying effect of the lever action pulling out the locating pin A embedded in the circuit board carrying plate B. While it cannot be denied that such an approach is certainly capable of achieving the objective of locating pin removal, following long-term utilization, manufacturers have discovered several obvious shortcomings that await and, furthermore, require improvement, including:
1. Since the locating pins A are tightly nailed into the circuit board carrying plate B, when the pincing tool 70 clamps in the prying approach to effect extraction, the locating pin A is pulled out in a curved line, generating considerable friction against the circuit board carrying plate B and, as such, the operator must exert more strength, the operation obviously consuming too much energy and is inconvenient.
2. Since the curved section 701 of the pincing tool 70 serves continuously as the fulcrum for prying out locating pins A and, furthermore, the downward pressure on the handle 702 is excessively great and unequal, the said curved section 701 is subjected to repeated stress and easily becomes uneven following prolonged usage, which obviously shortens its service life.
3. Since the said locating pin A is tightly implanted in the circuit board carrying plate B and, furthermore, is a small diameter component (most between approximately 1 mm and 5 mm), when the pincer tool 70 extracts, a larger force is required for clamping and, at the same time, a greater force bears down on the handle 702 to the extent that the said locating pin A is frequently severed by the pincer tool 70 and, as such, the objective of extraction cannot be completed and which may even risk the obvious hazard and drawback of having the said severed locating pin A propelled into the eyes of the operator (manufacturers today will not tolerate such a drawback).